The reconstruct of impaired enteric neural circuits at the thick granulation tissue at anastomosis in small intestine of H-line: Thy1 promoter GFP mouse was observed by two-photon microscopy (2PM) a week after drinking a 5-HT4-receptor agonist, mosapride citrate (MOS) 100 microM solution.In Thy1-promoter YFP mouse after gut transection and anastomosis, the fetal brain-derived neural stem cells (NSC) with red fluorescent cell linker were transplanted from the tail vein. 5-HT4 receptor-mediated facilitation of neurogenesis was confirmed by clear three-dimensional in vivo imaging of newborn enteric neurons generated from enteric neural progenitors (host NSC; green fluorescence) and those from transplant NSC (red fluorescence). The facilitating effect of MOS and the distribution of new neurons were similar between the transplant and host NSC.Finally, though preliminary, we succeeded in in vivo Ca2+ imaging of myenteric neuronal activity in the normal ileum of GCaMP6 transgenic mouse.